The instant invention relates to electrolytic timers and more particularly to an electronic timer circuit which utilizes a solid electrolytic timing device for measuring a predetermined, elapsed time period.
Numerous electronic timers have been produced which indicate lengthy time periods, as for instance, time periods in excess of several hundred hours. One of the problems with prior timing devices has been accuracy of measurement within a reasonable or permissible percent of total elapse time without employing more complicated and expensive electromechanical clock mechanisms.
Electrolytic timer devices have been employed in the past, but the use of electrolyte solutions requires manufacturing techniques that assure long shelf-life and operation without leaking, changing their physical and performance dimensions or creating operating hazards. Electroplating techniques have been used for inexpensive timers in the past to indicate elapsed time by visual observation of a deposit. However, determining the elapsed time period is inconvenient and as might be appreciated quite inaccurate. If a mechanical timer device is used in a circuit, a switching mechanism is required and this adds to the expense of the timer. So-called "one-shot" timers are known but must be thrown away after the period for which they are designed has elapsed.
The only prior art of which applicant is aware and which is related to the invention herein are disclosed in U.S. Pat. Nos. 3,355,731 and 3,769,557.